Historical
ASTM D7891-15
Standard Test Method for Shear Testing of Powders Using the Freeman Technology FT4 Powder Rheometer Shear Cell
1.1 This method covers the apparatus and procedures for measuring the incipient failure properties of a powder as a function of the normal stress for a given level of consolidation. The method also allows the further determination of the unconfined yield strength, internal friction angles, cohesion, flow function, major principal stress and wall friction angle (with the appropriate wall coupon fitted to the correct accessory).
1.2 These parameters are most commonly used for the design of storage hoppers and bins using industry standard calculations and procedures. They can also provide relative classification or comparison of the flow behavior of different powders or different batches of the same powder if similar stress and shear regimes are encountered within the processing equipment.
1.3 The apparatus is suitable for measuring the properties of powders with a maximum particle size of 1 mm. It is possible to test powders which have a small proportion of particles of 1 mm or greater, but they should be present in the bulk sample as no more than 5 % of the total mass in samples with a normal (Gaussian) size distribution.
1.4 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.
1.5 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
ASTM International [astm]